In my opinion, however, the crème de la crème of foliage rhododendrons has got to be the thick-flowered rhododendron. Although new foliage emerges golden blond, the surface turns silvery white and its underside turns a rich cinnamon rust shade. The tomentum of this dwarf species, which is suitable for even the smallest garden, lasts nearly all summer. The flowers, typical of many foliage rhododendrons, are pale pink to white. While the thick-flowered rhododendron may be difficult to find, its hybrid, ‘Golfer’, is more readily available. A cross between yakushimanum and thick-flowered rhododendron, ‘Golfer’ falls midway between both parents in leaf shape and plant size; but, like both its parents, this offspring is another foliage showstopper.
Closer to home is our own Labrador tea. This hardy native shrub is commonly encountered in acidic peatland habitats, but can be grown as a lovely garden plant. Labrador tea’s leaves emerge completely covered in long, white hairs. As the summer progresses, the upper leaf surface becomes wrinkled and veiny while its underside becomes coated in cinnamon indumentum. As a bonus, its foliage is pleasantly fragrant when rubbed.
Some foliage rhododendrons have rounded, not lance-shaped, foliage, such as the diminutive Williams rhododendron. Its small leaves unfurl bronzy red, with clear pink, bell-shaped flowers that are huge in relation to the shrub’s size.
There are several other foliage rhododendrons without indumentum and tomentum that, despite this lack, are also lovely during the winter months. The leaves of some of the popular PJM group, for example, turn a shiny burgundy to plum purple during the colder months, contrasting beautifully with other evergreens in the landscape, not to mention the snow. Among the best of these cultivars are ‘Thunder’, ‘Black Satin’ and ‘Midnight Ruby’.
Another rhododendron deserving special attention for its foliage is ‘Carmen’, a dwarf hybrid with a prostrate habit and relatively large, bell-shaped, blood-red flowers. It’s a spectacular shrub for a rock garden or the front of an ericaceous (acid-loving) border. Small, shiny, deep green, wrinkled foliage—reminiscent of that on Rosa rugosa—is an added bonus.
Most of these plants thrive in the Memorial University of Newfoundland Botanical Garden, despite the fact that we are considered Zone 5. Adequate winter protection in the form of three to five centimetres of compost (which is all the fertilizer these plants require) and placement in sheltered locations allows us to successfully push our zone rating.